Beleaguered South African President Jacob Zuma on Tuesday faced a no-confidence vote in parliament for a second time in less than a year and a legal bid to reinstate corruption charges against him.

The mounting pressure on the president comes against a background of economic crisis sparked by his firing of two finance ministers within days in December.

The fallout was followed by a public row between the respected new Finance Minister Pravin Gordhan and the head of the tax authority, which has again rattled markets.

The no-confidence vote was called by the official opposition, the Democratic Alliance (DA).

"South Africans demand that Jacob Zuma be taken to task for his reckless handling of our economy, and his sending South Africa into financial crisis," DA leader Mmusi Maimane said in a statement.

"A motion of no confidence is the best mechanism to ensure that President Zuma is fired, once and for all.

"It has become common cause that under Jacob Zuma's leadership, our country is spiralling downward - and doing so at an alarmingly fast rate."

MAJORITY

The motion is highly unlikely to succeed as Zuma's African National Congress (ANC) has an overwhelming majority in parliament, with 62 percent of the seats.

The DA has asked for a secret ballot, so ANC lawmakers who would like to see Zuma go can vote without fear of retribution — but that is not expected to be granted.

DA chief whip John Steenhuisen said that in response to a DA campaign, more than a million online letters lobbying ANC lawmakers to support the motion against Zuma had been sent in the run-up to the vote.

"This is... a clear indication that South Africans are increasingly tired of the president's poor performance and are putting their support behind the opposition," he said.

The DA is also pursuing an attempt in the High Court in Pretoria to reinstate charges of corruption against Zuma that were dropped in 2009, shortly before he became president.

The charges, which relate to a multibillion-dollar arms deal signed in 1999, were dropped allegedly because of interference in the prosecution case by his political opponents.

A statement from the presidency on Monday described the court proceedings as "an abuse of process by a political party in order to advance a political agenda.

"Through his submissions to the High Court, President Zuma will maintain that the decision (to drop the charges) was rationally derived at."

RACISM

The ANC has also described the DA's no-confidence motion as "a frivolous stunt" designed to divert public attention from "the racism scandals embarrassing the party on an ongoing basis".

The DA is seen as the political home of many South African whites after the end of apartheid more than 20 years ago, and the ANC has stepped up its attacks on alleged racism in the party ahead of municipal elections later this year.

While Zuma is expected to easily survive the no-confidence debate, analysts say heavy losses for the ANC in the elections could turn the party against the president.

"Zuma has been under pressure in the past but now it's coming from multiple angles," Susan Booysen of the University of the Witwatersrand, told AFP.

"There's nowadays dissident voices in the ANC. The support of Zuma is weaker but not to the point of collapse," she said.

"If ANC suffers badly in local elections it could be a signal they can't approach national elections (in 2019) with him in charge."

Zuma will have completed two terms in 2019 and is not eligible to run for president again, but if opposition to him continues to mount, the party could replace him ahead of the vote.